Xphos ligand and platinum catalysts: A versatile catalyst for the synthesis of functionalized β-(E)-vinylsilanes from terminal alkynes

Article abstract of DOI:10.1016/j.jorganchem.2008.05.028

Hydrosilylation of functionalized terminal arylalkynes with a variety of silanes catalyzed by PtCl₂ or PtO₂ in the presence of the air-stable and bulky Xphos ligand was investigated. Regardless of the electronic nature (electron withdrawing or donating group) and the position (o, m, p) of the substituents on the aromatic ring, a single β-(E)-styrylsilanes was obtained in good to excellent yields. The regioselectivity of the H-Si bond addition was found to be governed by steric effects induced by the bulky Xphos ligand. A dramatic regioselectivity was also observed when functionalized terminal aliphatic alkynes were employed as a substrate and in these cases regioisomeric β-(E)-vinylsilanes were generated with excellent selectivity.

Full text of DOI:10.1016/j.jorganchem.2008.05.028

Journal of Organometallic Chemistry 693 (2008) 2789–2797
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Xphos ligand and platinum catalysts: A versatile catalyst for the synthesis
of functionalized b-(E)-vinylsilanes from terminal alkynes
*
Abdallah Hamze, Olivier Provot, Jean-Daniel Brion, Mouâd Alami
Univ. Paris-Sud, CNRS, BioCIS, UMR 8076, Laboratoire de Chimie Thérapeutique, Faculté de Pharmacie, rue J.B. Clément, F-92296 Châtenay-Malabry, France
Institut de Chimie des Substances Naturelles, CNRS, avenue de la Terrasse, F-91198 Gif sur Yvette, France
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 11 April 2008
Received in revised form 22 May 2008
Accepted 22 May 2008
Available online 29 May 2008
Hydrosilylation of functionalized terminal arylalkynes with a variety of silanes catalyzed by PtCl2 or PtO2
in the presence of the air-stable and bulky Xphos ligand was investigated. Regardless of the electronic nat-
ure (electron withdrawing or donating group) and the position (o, m, p) of the substituents on the aromatic
ring, a single b-(E)-styrylsilanes was obtained in good to excellent yields. The regioselectivity of the H-Si
bond addition was found to be governed by steric effects induced by the bulky Xphos ligand. A dramatic
regioselectivity was also observed when functionalized terminal aliphatic alkynes were employed as a
substrate and in these cases regioisomeric b-(E)-vinylsilanes were generated with excellent selectivity.
Ó 2008 Elsevier B.V. All rights reserved.
Keywords:
Alkynes
Phosphane ligands
Hydrosilylation
Regioselectivity
Platinum
1. Introduction
silane, the metal species and the ligand. With (EtO)2MeSiH, the
branched
a
-isomer is best obtained in the presence of a cationic
*
The hydrosilylation of terminal alkynes with transition-metal
catalysts remains an area of intense research interest [1] as it pro-
vides a simple and straightforward, atom-economical method for
the synthesis of vinylsilanes [2]. Their low cost, high chemical sta-
bilities associated to a lack of toxicity make them ideal candidates
for palladium-catalyzed cross-coupling reactions [3]. Vinylsilanes
also constitute versatile starting materials for natural products
[4] and polymers [5]. The main difficulty with the hydrosilylation
reaction is control of the stereo- and regiochemistry of the alkenyl-
silanes products. For example, hydrosilylation of terminal alkynes
may give a primary mixture of three isomeric vinylsilanes includ-
ing the b-(Z)- and b-(E)-linear vinylsilanes as well as the branched
Ru complex [Cp Ru(MeCN)3]PF6 [6]. Using ruthenium carbene
complexes [7] or [RuCl2(p-cymene)]2 [8] as well as [Cp IrCl2]2 [9]
*
catalysts, selective formation of stereoisomeric b-(Z)-vinylsilanes,
is generally achieved. The formation of the third b-(E)-isomer is
best accomplished by using Rh-[10] Ir-[11] and Pd-based [12] cat-
alysts. With platinum catalyst which holds certain supremacy in
the cis-hydrosilylation of alkynes, low to moderate regioselectivi-
ties were generally observed with terminal arylalkynes when using
industrial catalysts such as Speier’s (H2PtCl6) and Karstedt’s cata-
lysts (Pt2(dvtms)3; dvtms = divinyltetramethyldisiloxane) [13].
The importance of bulky ligands effect for achieving b-(E) selectiv-
ities was reported. The use of Pt catalysts associated with
P(cC6H11)3 [14] or P(t-Bu)3[15] as the catalysts systems was shown
to display moderate to high b-(E)-selectivities depending on the
silane employed. Changing the air-sensitive and pyrophoric
P(t-Bu)3 to the sterically aminomonophosphine ligand P(i-BuN-
CH2CH2)3N [16] also led to b-(E) selectivity when using Ph3SiH or
Et3SiH. To our knowledge, however, such hydrosilylation reactions
were only studied with the simple substrate phenylacetylene (1a).
The remaining challenge is to obtain high b-(E)-selectivity from
functionalized arylalkynes without compromising reagent stability
and practicality. Therefore, considering the potential utility of
b-(E)-styrylsilanes 2 in synthetic organic chemistry [17], the search
of an efficient and versatile catalytic system for the highly selective
formation of 2 with various silanes is strongly desirable and
presents an interesting challenge.
a-isomer (Scheme 1).
Although metal-catalyzed hydrosilylation of terminal aliphatic
alkynes is well documented [1], however the reaction with termi-
nal arylalkynes, particularly those bearing functionalized groups
on the aromatic ring, has received scant attention probably be-
cause of the difficulty in controlling the regioselectivity of the
H–Si bond addition. The regio- and stereochemical outcome of this
reaction depends on several factors including the nature of the
* Corresponding author. Address: Univ. Paris-Sud, CNRS, BioCIS, UMR 8076,
Laboratoire de Chimie Thérapeutique, Faculté de Pharmacie, rue J.B. Clément,
F-92296 Châtenay-Malabry, France.
E-mail address: mouad.alami@u-psud.fr (M. Alami).
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2008.05.028

2790
A. Hamze et al. / Journal of Organometallic Chemistry 693 (2008) 2789–2797
Table 1
R
R
Y3SiH
α
β
Screening of solvents and phosphines ligands for platinum-catalyzed hydrosilylation
of phenylacetylene (1a) with triethylsilane
R
SiY3
+
+
R
SiY3
Y3Si
α-isomer
MLn (cat.)
β-(Z)-isomer
β-(E)-isomer
R
R
Scheme 1.
Et3SiH
α
β
+
[Pt]/2 L, 60 °C
solvent, 1 h
Et3Si
α -isomer
R
SiEt3
2
1
3
Previously, we reported that heterogeneous commercially avail-
able platinum oxide (PtO2) proved to be a versatile catalyst for the
hydrosilylation of internal arylalkynes [18]. Unfortunately, in the
case of terminal alkynes, the regioselectivity of the H–Si bond addi-
tion with triethysilane was found to be weak providing a mixture
β -(E)-isomer
a: R = H
Entry [Pt]
L
Solvent
a
/ba ratio
Conv.a (%)
Yieldb (%)
of the branched a-isomer and b-(E)-vinylsilane isomer. To ensure
1 PtO2
2 PtO2
3 PtO2
4 PtO2
5 PtO2
6 PtO2
7 PtO2
8 PtO2
–
–
–
–
–
–
–
–
–
15:85
10:90
9:91
20:80
24:76
10:90
8:92
12:88
–
4:96
0:100
0:100
–
19:81
15:85
10:90
0:100
3:97
100
100
100
100
100
100
100
100
0
100
15
100
0
13
14
12
10
100
100
100
86c
88
95
62
68
71
67
45
–
92
nd
96
–
the synthetic utility of terminal arylalkynes hydrosilylation, both
the regio- and stereoselectivity of this process must be addressed.
Therefore, we anticipated that the tuning of platinum complex cat-
alysts (platinum species and ligands) would affect the regioselec-
tivity of H–Si bond addition. Herein, our detailed study is
reported [19]. We found that the use of 2-dicyclohexyl-phos-
phino-20,40,60-triisopropylbiphenyl (Xphos) (Scheme 3) associated
with PtO2 or PtCl2 proved to be efficient and versatile catalytic sys-
tems for the highly selective formation of b-(E)-styrylsilanes 2. The
selectivity issues of this reaction mediated by platinum have been
studied extensively and contributions of steric, electronic and
coordinative factors controlling this regioselectivity are discussed.
C6H6
THF
DMF
NMP
H2O
EtOH
HFIPd
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
9 PtO2
PPh3
PCy3
Pt-Bu3
Xphose
dppp
dppb
dppf
BINAP
Xphos
Xphos
Xphos
Xphos
10 PtO2
11 PtO2
12 PtO2
13 PtO2
14 PtO2
15 PtO2
16 PtO2
17 Pt/C
18 H2PtCl6
19 PtCl4
20 PtCl2
ndf
nd
nd
nd
56
75
98
2. Results and discussion
0:100
0:100
For optimization of our reaction conditions, the hydrosilylation
of commercially available phenylacetylene with triethylsilane was
chosen as a model substrate to evaluate the effects of various sol-
vents, platinum catalysts and ligands. The results are summarized
in Table 1.
a
Determined by GC analysis and 1H NMR in the crude reaction mixture.
b
Isolated yield of the mixture of vinylsilanes
chromatography.
2 and 3 after column
c
At room temperature, the reaction required 16 h for completion and led to a
10:90 /b ratio in a 76% yield.
a
d
Hexafluoroisopropanol.
By using a 1:1 ratio of Pt:L (5 mol%), 3a was exclusively formed (a:b = 0:100) in
e
82% yield.
2.1. Optimization of the platinum-catalyzed hydrosilylation of
phenylacetylene
f
nd: not determined.
To begin our study, phenylacetylene 1a was reacted with Et3SiH
(1.5 equiv.) in the presence of PtO2 (5 mol%). Without solvent at
60 °C, the reaction proceeded in 1 h and gave a 15:85 mixture of
vinylsilanes 2a and 3a and no b-(Z)-isomer was detected (Table
1, entry 1). Performing the reaction at room temperature resulted
in a similar selectivity but with a prolonged reaction time (16 h).
We next investigated the hydrosilylation in various solvents and
found that similar selectivities were obtained when C6H6 and
THF were employed (entries 2 and 3). Use of other non-protic polar
solvents such as DMF or NMP provided a slightly lower b-(E)-selec-
tivity (entries 4 and 5). Employment of both EtOH, HFIP or H2O can
replace THF to achieve same level of selectivity (entries 6–8).
As the ligand nature has been previously shown to affect the
hydrosilylation selectivity [14,16], we examined the process in
the presence of a range of phosphine ligands. With PtO2/PPh3 as
the catalytic system, no reaction took place (entry 9). Changing
the monodentate ligand triphenylphosphine to electron rich and
bulky ligand PCy3 gave an excellent b-(E)-selectivity (entry 10)
whereas P(t-Bu)3 induced a dramatic lowering of the conversion
rate (entry 11). We were delighted to find that the catalytic activity
of the heterogeneous PtO2/Xphos system proved to be superior to
the catalyst couple PtO2/PCy3 leading, with an excellent yield, to
a total control of the b-(E)-selectivity (entry 12). The use of biden-
tate phosphine ligands (dppp, dppb, dppf or BINAP) however, in-
duced a dramatic lowering of the conversion rate associated with
Considering its high catalytic activity, ligand Xphos was evalu-
ated with other platinum sources. With heterogeneous Pt/C,
although a total b-(E)-selectivity was obtained the conversion rate
was mediocre (entry 17). Next, homogeneous platinum catalysts
were examined. Speier’s (H2PtCl6) catalyst associated with Xphos
afforded a high b-regiocontrol (a:b = 3:97) within a moderate iso-
lated yield (entry 18). More interestingly, a total control of the b-
(E)-selectivity was observed when using the catalyst systems
PtCl4/Xphos or PtCl2/Xphos with good to excellent isolated yield
respectively (entries 19 and 20). Finally, the increase of the amount
of catalyst, ligand or silane, had no significant improvement in the
yield of the hydrosilylation reaction.
2.2. Hydrosilylation of phenylacetylene with various hydrosilanes
As the silane source is well-known to influence the a:b distribu-
tion [13a], we examined the effect of other hydrosilanes under
our optimized conditions and the results of this screening are
presented in Table 2.
Contrary to our expectation, all the hydrosilanes examined
including PhMe2SiH, Ph2MeSiH, EtOMe2SiH or (EtO)3SiH showed
an exclusive b-regiocontrol. Therefore, Xphos associated with
either PtO2 or PtCl2 proved to be a versatile and efficient ligand
for the hydrosilylation of phenylacetylene with various
hydrosilanes.
a significant change on the a:b ratio (entries 13–16).

A. Hamze et al. / Journal of Organometallic Chemistry 693 (2008) 2789–2797
2791
Table 2
effects of substituents. However, with ortho-methoxycarbonyl
phenylacetylene (1j), the PtCl2-catalyzed hydrosilylation was less
selective and led to a regioisomeric mixture with a preference for
PtO2/Xphos and PtCl2/Xphos complexes-catalyzed hydrosilylation of phenylacetylene
(1a) with various hydrosilanes
the b-isomer (
ODE, which is opposed to steric effects, [18a] rebalance the iso-
meric distribution, thus increasing the amounts of -adduct. To
a:b = 19:81, entry 10). This result clearly shows that
Y3SiH
α
β
Ph
Ph
a
Ph
+
[Pt]/Xphos,
60 °C, THF, 1 h
show the versatility of the PtCl2/Xphos couple, we examined its
catalytic activity with alkynes having an electron donating group.
Thus, the hydrosilylation of both para- and ortho-methoxyphenyl-
acetylene exclusively produced the desired b-(E) vinylsilanes 2
with excellent yields (entries 11 and 12). In the following example
(entry 13), it is interesting to note that 2-pyridylacetylene was
regioselectively hydrosilylated with Et3SiH and PtCl2/Xphos couple
without any difficulties. After completing cursory investigation of
functionalized terminal arylalkynes, further examination revealed
that the PtCl2/Xphos system efficiently catalyzes the hydrosilyla-
tion of terminal aliphatic alkynes. With triethylsilane, reactions
gave complete conversion of the substrate alkynes 1l and 1m at
60 °C within 1 h to afford exclusively their corresponding b-(E)-
vinylsilanes 2p and 2q, respectively (entries 14 and 15).
We were also pleased to observe that the PtCl2/Xphos couple
was still efficient with aliphatic alkynes bearing a primary or sec-
ondary alcohol function (entries 16 and 17). Inspired by the suc-
cess of the versatile and easy to handle PtCl2/Xphos catalyst
system, we turned our attention to the preparation of a variety
of functionalized vinylalkoxysilanes. The results of this study are
reported in Table 4 and clearly indicated the efficiency of the pres-
ent methodology.
Y3Si
SiY3
-isomer
α-isomer β-(E)
Entry [Pt]
Y3SiH
a
/b ratioa
b-(E)-vinylsilane 2
Yieldb (%)
SiMe2Ph
1 PtO2
2 PtCl2
PhMe2SiH
PhMe2SiH
0:100
0:100
96
94
2b
SiPh2Me
Ph
3 PtO2
4 PtCl2
Ph2MeSiH
Ph2MeSiH
0:100
0:100
95
97
2c
Ph
5 PtO2
6 PtCl2
EtOMe2SiH
EtOMe2SiH
0:100
0:100
61c
64c
SiMe2OEt
2d
Si(OEt)3
Ph
7 PtO2
8 PtCl2
(EtO)3SiH
(EtO)3SiH
0:100
0:100
72
68
2e
Ph
Determined by GC analysis and 1H NMR in the crude reaction mixture.
Isolated yield.
Reaction was performed at room temperature within 12 h. At 60 °C, less than 2%
a
b
c
of a-isomer was detected.
2.3. Scope and limitations
Performing the reaction with various alkoxysilanes resulted in
the formation of vinylalkoxysilanes 2t-z in good yields. Electron-
donating and electron-withdrawing substituents on the aromatic
ring did not interfere with the outcome of the present reaction
and similar yields and selectivities were obtained (entries 1–5).
Further examination revealed that the PtCl2/Xphos system effi-
ciently catalyzed the hydrosilylation of aliphatic alkynes. Complete
conversion of the starting alkynes was observed within 1 h afford-
ing exclusively their corresponding b-(E)-vinyldimethylethoxysil-
anes in good yields (entries 6 and 7) showing in this manner the
general character of the present process.
The synthetic utility of b-(E)-styrylalkoxysilanes was success-
fully demonstrated in the Hiyama coupling reaction [3]. Thus,
selective palladium-catalyzed cross-coupling of styryldimethyleth-
oxysilane 2u with iodobenzene according to Trost’s conditions [21]
resulted in the formation of the coupling product in good yield 85%
(Scheme 2).
We next selected the PtO2/Xphos catalyst system for evaluating
the scope of this hydrosilylation with a range variety of functional-
ized terminal arylalkynes. As seen in Table 3, functionalized aryl-
alkynes were converted in 1 h at 60 °C with Et3SiH to the
corresponding vinylsilanes in good to excellent yields. Analysis of
the crude reaction mixtures by 1H NMR spectroscopy revealed
no trace of the b-(Z)-vinylsilanes demonstrating that the H–Si
bond addition proceeded exclusively in a syn fashion. Additionally,
the reaction exhibited
vinylsilanes.
a remarkable selectivity for b-(E)-
Arylalkynes with a para- or a meta-electron donating group (e.g.
EDG = OMe, Me) were cleanly hydrosilylated in the presence of
PtO2/Xphos couple to their corresponding b-(E)-adducts with
excellent yields (entries 1, 2 and 4). One can note that in the ab-
sence of any ligand, hydrosilylation of para-methoxyphenylacety-
lene (1b) produced a 18:82 mixture of
a:b adducts. Next, we
3. Mechanistic considerations
evaluated the influence of ortho substituents on the reaction selec-
tivity [20]. By switching the substituent group from the para or
meta to the ortho position, again a total b-regiocontrol was ob-
served (entries 3 and 5). This result clearly demonstrated that
the regioselectivity of the H–Si bond addition is governed by steric
effects induced by Xphos ligand rather than ortho-directing effect
(ODE) as we previously reported [18]. To support this explanation,
the hydrosilylation of ortho methoxyphenylacetylene was con-
Although there is no clear experimental evidence, it is interest-
ing to speculate on the mechanism of the hydrosilylation reaction
that rationalizes the observed b-(E)-selectivity. Initially, the PtCl2L2
complex is formed from PtCl2 and Xphos ligand [22] which is then
reduced with the silane to metal platinum(0) catalyst, associated
with one or two ligands. The next step involves oxidative addition
of the silane to the platinum species to generate the platinum com-
plex I or II and a further coordination with the alkyne would afford
species III (Scheme 3).
Then the alkyne would insert into the Pt–H bond (Chalk–Harrod
mechanism) rather than Pt–Si bond as was suggested by ab initio
molecular orbital and Møller–Plesset perturbation theory calcula-
tions [23]. In the presence of Xphos ligand, the total selectivity
for the b-(E)-isomers 2 can be rationalized by the formation of
the species A as it would be sterically less demanding and consti-
tutes the unique pathway to furnish vinyl organometallic IV, while
species B, is more congested due to steric repulsion between the R
substituent and the hindered Xphos ligand. This argument is
ducted without Xphos and produced
regioisomers.
a 38:62 ratio of a:b
Encouraged by these findings, we examined the reaction with
terminal arylalkynes having an electron withdrawing group. Sur-
prisingly under the above optimized conditions (PtO2/Xphos), no
reaction took place with para-methoxycarbonyl phenylacetylene
(entry 6). We were pleased to observe however, that using the
alternative PtCl2/Xphos catalytic system the hydrosilylation pro-
ceeded cleanly leading to a single b-(E)-vinylsilane in excellent
yield (entry 7). Similarly, a total b-(E)-selectivity was also observed
with p-CN and p-Br-substituted phenylacetylene (entries 8 and 9)
indicating clearly that steric effects totally supplant electronic

2792
A. Hamze et al. / Journal of Organometallic Chemistry 693 (2008) 2789–2797
Table 3
PtO2/Xphos and PtCl2/Xphos complexes-catalyzed hydrosilylation of various functionalized terminal alkynes with triethylsilane
Et3SiH
α
β
R
R
R
+
[Pt]/Xphos,
60°C, THF, 1 h
EtSi
SiEt3
α-isomer β-(E)-isomer
Entry
1
Alkyne 1
[Pt]
a
/ba ratio
Vinylsilanesb
2
Yieldc (%)
91
0:100d
MeO
2f
PtO2
MeO
1b
SiEt3
1c
2
PtO2
0:100
92
2g
2h
MeO
SiEt3
MeO
OMe
1d
3
4
5
6
7
8
9
PtO2
PtO2
PtO2
PtO2
PtCl2
PtCl2
PtCl2
0:100e
0:100
0:100
–
98
88
93
0f
SiEt3
OMe
Me
2i
2j
1e
Me
SiEt3
Me
1f
SiEt3
Me
MeO2C
MeO2C
NC
2k
2k
MeO2C
MeO2C
NC
1g
1g
SiEt3
SiEt3
0:100
0:100
0:100
86
80
94
2l
1h
1i
SiEt3
Br
2m
Br
SiEt3
CO2Me
SiEt3
CO2Me
1j
2n
3j
10
11
12
13
14
15
16
17
PtCl2
PtCl2
PtCl2
PtCl2
PtCl2
PtCl2
PtCl2
PtCl2
19:81
0:100
0:100
0:100
0:100
0:100
0:100
0:100
83g
88
SiEt3
CO2Me
MeO
2f
MeO
1b
SiEt3
OMe
1d
1k
2h
92
SiEt3
OMe
2o
2p
98h
93
N
N
SiEt3
SiEt3
C5H11
1l
1m
1n
C5H11
Me
Me
96
2q
2r
MeO
HO
SiEt3
MeO
96i
96
SiEt3
HO
HO
C5H11
HO
2s
SiEt3
1o
C5H11
a
Determined by 1H NMR in the crude reaction mixture.
b
c
d
e
f
All of the reported compounds exhibited spectral data in agreement with the assigned structures.
Isolated yield.
A 18:82
A 38:62
a
a
:b mixture was obtained in the absence of Xphos ligand.
:b mixture was obtained in the absence of Xphos ligand.
Reproducible result after three runs and starting alkyne was recovered unchanged.
Isolated yield of the vinylsilane a:b mixture after column chromatography.
10 mol% of PtCl2 and 20 mol% of Xphos were used.
Reaction was performed at r.t.
g
h
i
consistent with the fact that in the absence of ligand, the hydrosi-
lylation exhibited a poor regioselectivity (see footnotes d and e,
Table 3) probably due to the diminished steric requirements
around the platinum center in both species C and D.

A. Hamze et al. / Journal of Organometallic Chemistry 693 (2008) 2789–2797
2793
Table 4
Preparation of functionalized b-(E)-vinylalkoxysilanes
complex
2
using the PtCl2/Xphos
+2L
PtCl2
PtCl2L2
P
=
L
i-Pr
2 HSiY
3
R
i-Pr
H-[Si]
Xphos
R
i-Pr
-L
[PtCl2]/Xphos,
Pt0L2
Pt0L
[Si]
+L
60 °C, THF, 1 h
β-(E)-isomer
HSiY
3
HSiY
3
2
Entry
1
Vinylalkoxysilanes 2a
a
/b ratiob
Yieldc(%)
65
Si(OEt)3
2:98
R
L
2t
H-Pt-SiY3
MeO
MeO
Y3SiPt
H
H-Pt-SiY3
II
L
I
L
SiMe2OEt
2u
IV
L
2
0:100
83d
Si(OEt)3
3
4
2:98
3:97
83
68
R
2v
Me
SiMe2OEt
-L
R
2w
R
MeO2C
Si(OEt)3
H-Pt-SiY3
5
6
0:100
0:100
75
94
2x
L
III
Me
SiMe2OEt
C5H11
EtO
2y
R
R
H
R
L
H
R
H
SiMe2OEt
H
72d
Pt
7
0:100
L
Pt
Pt
Y3Si
2z
Pt
Y3Si
OEt
SiY3
SiY3
a
A
B
C
D
All of the reported compounds exhibited spectral data in agreement with the
assigned structures.
favored
not favored
less favored
favored
b
Determined by GC analysis and 1H NMR in the crude reaction mixture.
c
Transition states with Xphos ligand
Transition states without ligand
Isolated yield.
Scheme 3. Proposed Chalk–Harrod mechanism for the platinum-catalyzed hydro-
silylation of terminal alkynes.
Pd2(dba)3.CHCl3 (3 mol%)
Ph
85%
TBAF (2.2 eq),
2u
THF, PhI (1.5 eq)
0 ˚C to rt, 3 h
MeO
graphy: cyclohexane, ethyl acetate (EtOAc), were technical grade.
Tetrahydrofuran (THF) was distilled under argon from sodium-
benzophenone ketyl.
Scheme 2.
The compounds were all identified by usual physical methods,
i.e. 1H NMR, 13C NMR, IR, elemental analysis. 1H and 13C NMR spec-
tra were measured in CDCl3or DMSO-d6 with a Bruker ARX 400 or
Bruker Avance 300 and chemical shifts are reported in ppm. The
following abbreviation are used: m (multiplet), s (singlet), br s
(broad singlet), d (doublet), t (triplet) dd (doublet of doublet), td
(triplet of doublet), q (quadruplet). IR spectra were measured on
a Bruker Vector 22 spectrophotometer (neat, cmꢀ1). Elemental
analyses were performed with a Perkin–Elmer 240 analyser. Ana-
lytical TLC was performed on Merck precoated silica gel 60F plates.
Merck silica gel 60 (230–400 mesh) was used for column
chromatography.
4. Conclusion
In conclusion, we have demonstrated that the use of the com-
mercially available PtO2 or PtCl2 catalysts in conjunction with the
air-stable and bulky Xphos ligand constitutes a versatile combina-
tion for the selective hydrosilylation of a series of functionalized
terminal arylalkynes as well as aliphatic alkynes. Results from
these studies indicated that various silanes including alkoxysilanes
could be used successfully to provide b-(E)-vinylsilanes with high
or even total selectivity. This catalytic hydrosilylation protocol is
characterized by its excellent chemo, regio-, and stereoselectivity,
functional group compatibility and mild reaction conditions. It rep-
resents a very attractive procedure for the univocal synthesis of
b-(E)-vinylsilanes from terminal alkynes and should find many
applications in organic synthesis. Future developments will focus
on several synthetic applications of these vinylsilanes.
5.2. Experimental procedure for the PtCl2or PtO2-catalyzed
hydrosilylation of terminal alkynes
Under a nitrogen atmosphere, PtCl2 (13 mg; 0.05 mmol) or PtO2
(11 mg; 0.05 mmol) and Xphos (48 mg; 0.1 mmol) in THF (0.5 mL)
were heated at 60 °C for 15 min. Then, terminal alkyne (1 mmol)
and hydrosilane (1.5 mmol) were successively added via syringe
and the mixture was stirred at 60 °C for 1 h. After evaporation of
the solvent, the residue was purified by column chromatography
to yield the (E)-vinylsilane 2.
5. Experimental
5.1. General
All glasswares were oven-dried at 140 °C and all reactions were
conducted under a nitrogen atmosphere. Solvents for chromato-

2794
A. Hamze et al. / Journal of Organometallic Chemistry 693 (2008) 2789–2797
5.2.1. (E)-1-triethylsilyl-2-phenylethene (2a) [16]
Yield: colorless oil, 98%.
1H NMR (300 MHz, CDCl3): d 1.29 (t, 9H, J = 7.0 Hz), 3.91 (q, 6H,
J = 7.0 Hz), 6.20 (d, 1H, J = 19.3 Hz), 7.24 (d, 1H, J = 19.3 Hz), 7.28–
7.39 (m, 3H), 7.50 (m, 2H).
TLC: Rf 0.61 (cyclohexane, SiO2).
IR (neat, cmꢀ1): 3023, 2952, 2909, 2874, 1603, 1574, 1494,
1458, 1416, 1236, 1198, 1072, 1012, 988, 827, 784, 734.
1H NMR (300 MHz, CDCl3): d 0.55 (q, 6H, J = 7.6 Hz), 0.87 (t, 9H,
J = 7.6 Hz), 6.31 (d, 1H, J = 19.3 Hz), 6.78 (d, 1H, J = 19.3 Hz), 7.12 (t,
1H, J = 7.3 Hz), 7.21 (d, 2H, J = 7.3 Hz), 7.33 (d, 2H, J = 7.3 Hz).
13C NMR (75 MHz, CDCl3): d 3.5 (3 CH2), 7.4 (3 CH3), 126.0 (CH),
126.3 (2 CH), 127.9 (CH), 128.5 (2 CH), 138.5 (C), 144.8 (CH).
MS(EI): 218 (M+).
13C NMR (75 MHz, CDCl3): d 18.3 (3 CH3), 58.6 (3 CH2), 117.7
(CH), 126.8 (2 CH), 128.6 (2 CH), 128.8 (CH), 137.6 (C), 149.2 (CH).
MS(ESI): 267 (M+H)+, 289 (M+Na)+.
Anal. Calc. for C14H22O3Si (266.41): C, 63.12; H, 8.32. Found: C,
62.97; H, 8.31%.
5.2.6. (E)-1-triethylsilyl-2-(4-methoxyphenyl)ethene (2f) [18b]
Yield: colorless oil, 91%.
Anal. Calc. for C14H22Si (218.41): C, 76.99; H, 10.15. Found: C,
77.12; H, 10.05%.
TLC: Rf 0.5 (Et2O/cyclohexane, 5/95, SiO2).
IR (neat, cmꢀ1): 2952, 2909, 2874, 2835, 1606, 1570, 1508,
1463, 1441, 1416, 1378, 1332, 1303, 1294, 1250, 1171, 1106,
1037, 1014, 986, 843, 789, 749, 717.
5.2.2. (E)-1-dimethylphenylsilyl-2-phenylethene (2b) [11]
Yield: colorless oil, 94%.
1H NMR (300 MHz, CDCl3): d 0.57 (q, 6H, J = 7.8 Hz), 0.90 (t, 9H,
J = 7.8 Hz), 3.72 (s, 3H), 6.17 (d, 1H, J = 19.3 Hz), 6.70–6.82 (m, 3H),
7.30 (d, 2H, J = 8.7 Hz).
TLC: Rf 0.40 (cyclohexane, SiO2).
IR (neat, cmꢀ1): 3067, 3023, 2956, 1605, 1573, 1494, 1447,
1427, 1334, 1248, 1215, 1196, 1114, 1068, 1028, 989, 844, 828,
808, 774, 726, 697, 689.
13C NMR (75 MHz, CDCl3): d 3.7 (3 CH2), 7.6 (3 CH3), 55.4
(OCH3), 114.0 (2 CH), 123.1 (CH), 127.6 (2 CH), 131.7 (C), 144.3
(CH), 159.6 (C).
1H NMR (300 MHz, CDCl3):
d 0.46 (s, 6H), 6.61 (d, 1H,
MS(ESI): 248 (M+).
J = 19.1 Hz), 7.00 (d, 1H, J = 19.1 Hz), 7.20–7.42 (m, 6H), 7.46 (d,
2H, J = 7.3 Hz), 7.53–7.65 (m, 2H).
Anal. Calc. for C15H24OSi (248.44): C, 72.52; H, 9.74. Found: C,
72.48; H, 9.82%.
13C NMR (75 MHz, CDCl3): d ꢀ2.5 (2 CH3), 126.5 (2 CH), 127.1
(CH), 127.8 (2 CH), 128.1 (CH), 128.5 (2 CH), 129.0 (CH), 133.0
(CH), 133.9 (CH), 138.1 (C), 138.5 (C), 145.3 (CH).
MS(EI): 238 (M+).
5.2.7. (E)-1-triethylsilyl-2-(3-methoxyphenyl)ethene (2g)
Yield: colorless oil, 92%.
TLC: Rf 0.54 (Et2O/cyclohexane, 5/95, SiO2).
Anal. Calc. for C16H18Si (238.40): C, 80.61; H, 7.61. Found: C,
80.47; H, 7.56%.
IR (neat, cmꢀ1): 2952, 2909, 2874, 2834, 1598, 1575, 1485,
1456, 1431, 1416, 1378, 1317, 1286, 1263, 1237, 1202, 1152,
1080, 1049, 1013, 986, 923, 906, 859, 794, 766.
1H NMR (300 MHz, CDCl3): d 0.58 (q, 6H, J = 7.8 Hz), 0.91 (t, 9H,
J = 7.8 Hz), 3.75 (s, 3H), 6.33 (d, 1H, J = 19.3 Hz), 6.70–6.74 (m, 1H),
6.78 (d, 1H, J = 19.3 Hz), 6.88–7.00 (m, 2H), 7.17 (t, 1H, J = 7.9 Hz).
13C NMR (75 MHz, CDCl3): d 3.6 (3 CH2), 7.5 (3 CH3), 55.4
(OCH3), 111.3 (CH), 113.8 (CH), 119.2 (CH), 126.4 (CH), 129.6
(CH), 140.12 (C), 144.8 (CH), 160.0 (C).
5.2.3. (E)-1-methyldiphenylsilyl-2-phenylethene (2c) [24]
Yield: colorless oil, 97%.
TLC: Rf 0.21 (cyclohexane, 100%, SiO2).
IR (neat, cmꢀ1): 3067, 3021, 2958, 1602, 1573, 1494, 1446,
1427, 1333, 1251, 1215, 1104, 1111, 834, 801, 785, 730.
1H NMR (300 MHz, CDCl3):
d 0.76 (s, 3H), 6.80 (d, 1H,
J = 19.1 Hz), 7.02 (d, 1H, J = 19.1 Hz), 7.26–7.47 (m, 9H), 7.51–
7.68 (m, 6H).
MS(ESI): 248 (M+).
Anal. Calc. for C15H24OSi (248.44): C, 72.52; H, 9.74. Found: C,
72.87; H, 9.54%.
13C NMR (75 MHz, CDCl3): d ꢀ3.6 (CH3), 125.0 (CH), 126.7 (2
CH), 128.0 (4 CH), 128.4 (CH), 128.6 (2 CH), 129.4 (2 CH), 135.0
(4 CH), 136.5 (2 C), 138.0 (C), 147.2 (CH).
MS(EI): 300 (M+).
5.2.8. (E)-1-triethylsilyl-2-(2-methoxyphenyl)ethene (2h) [18b]
Yield: colorless oil, 98%.
Anal. Calc. for C21H20Si (300.47): C, 83.94; H, 6.71. Found: C,
83.90; H, 6.82%.
TLC: Rf 0.70 (Et2O/cyclohexane, 30/70, SiO2).
IR (neat, cmꢀ1): 2952, 2909, 2874, 2835, 1596, 1485, 1462,
1437, 1416, 1327, 1288, 1241, 1211, 1176, 1161, 1104, 1050,
1030, 1015, 994, 973, 852, 833, 802, 747, 720.
1H NMR (300 MHz, CDCl3): d 0.59 (q, 6H, J = 7.8 Hz), 0.91 (t, 9H,
J = 7.8 Hz), 3.77 (s, 3H), 6.31 (d, 1H, J = 19.5 Hz), 6.75-6.92 (m, 2H),
7.10-7.30 (m, 2H), 7.47 (dd, 1H, J = 7.7 Hz, J = 1.5 Hz).
13C NMR (75 MHz, CDCl3): d 3.7 (3 CH2), 7.6 (3 CH3), 55.7
(OCH3), 111.1 (CH), 120.7 (CH), 126.2 (CH), 126.3 (CH), 127.9 (C),
129.0 (CH), 139.2 (CH), 156.7 (C).
5.2.4. (E)-1-ethoxydimethylsilyl-2-phenylethene (2d) [25]
Yield: yellow oil, 64%.
TLC: Rf 0.43 (Et2O/cyclohexane, 5/95, SiO2).
IR (neat, cmꢀ1): 3024, 2964, 2925, 1605, 1574, 1495, 1447,
1390, 1250, 1104, 1074, 1029, 991, 832, 813, 780, 758.
1H NMR (300 MHz, CDCl3): d 0.15 (s, 6H), 1.10 (t, 3H, J = 7.0 Hz),
3.60 (q, 2H, J = 7.0 Hz), 6.30 (d, 1H, J = 19.3 Hz), 6.90 (d, 1H,
J = 19.3 Hz), 7.09–7.25 (m, 3H), 7.33 (d, 2H, J = 6.9 Hz).
13C NMR (75 MHz, CDCl3): d ꢀ1.6 (2 CH3), 18.6 (CH3), 58.6 (CH2),
126.5 (CH), 126.7 (2 CH), 128.4 (CH), 128.6 (2 CH), 138.0 (C), 145.6
(CH).
MS(ESI): 248 (M+).
Anal. Calc. for C15H24OSi (248.44): C, 72.52; H, 9.74. Found: C,
72.64; H, 9.80%.
MS(ESI): 207 (M+H)+, 229 (M+Na)+.
Anal. Calc. for C12H18OSi (206.36): C, 69.84; H, 8.79. Found: C,
69.85; H, 8.70%.
5.2.9. (E)-1-triethylsilyl-2-(4-methylphenyl)ethene (2i) [26]
Yield: colorless oil, 88%.
TLC: Rf 0.60 (cyclohexane, SiO2).
IR (neat, cmꢀ1): 2952, 2909, 2874, 1608, 1566, 1510, 1458,
1415, 1377, 1236, 1197, 1178, 1115, 1014, 986, 842, 790, 778,
753, 715.
5.2.5. (E)-1-triethoxysilyl-2-phenylethene (2e) [24]
Yield: colorless oil, 70%.
TLC: Rf 0.23 (Et2O/cyclohexane, 5/95, SiO2).
1H NMR (300 MHz, CDCl3): d 0.81 (q, 6H, J = 7.9 Hz), 1.13 (t, 9H,
J = 7.9 Hz), 2.45 (s, 3H), 6.50 (d, 1H, J = 19.3 Hz), 7.02 (d, 1H,
J = 19.3 Hz), 7.26 (d, 2H, J = 8.0 Hz), 7.47 (d, 2H, J = 8.0 Hz).
IR (neat, cmꢀ1): 2974, 2885, 1603, 1574, 1495, 1447, 1390,
1293, 1219, 1197, 1166, 1099, 1071, 995, 956, 838, 775, 733.

A. Hamze et al. / Journal of Organometallic Chemistry 693 (2008) 2789–2797
2795
13C NMR (75 MHz, CDCl3): d 3.7 (3 CH2), 7.5 (3 CH3), 21.3 (CH3),
MS(EI): 296, 298 (M+).
124.5 (CH), 126.4 (2 CH), 129.3 (2 CH), 136.0 (C), 137.8 (C), 144.9
Anal. Calc. for C14H21BrSi (297.31): C, 56.56; H, 7.12. Found: C,
56.45; H, 7.20%.
(CH).
MS(EI): 232 (M+).
Anal. Calc. for C15H24Si (232.44): C, 77.51; H, 10.41. Found: C,
77.48; H, 9.95%.
5.2.14. (E)-1-triethylsilyl-2-(2-methoxycarbonyl phenyl)-ethene (2n)
Yield: colorless oil, 83% a/b (ca. 19/81) mixture of isomers.
TLC: Rf 0.42 (Et2O/cyclohexane, 5/95, SiO2).
5.2.10. (E)-1-triethylsilyl-2-(2-methylphenyl)ethene (2j) [26]
Yield: yellow oil, 93%.
IR (neat, cmꢀ1): 2951, 2909, 2874, 1721, 1598, 1563, 1475,
1458, 1433, 1416, 1289, 1256, 1200, 1126, 1076, 1047, 1011,
988, 819, 783, 740, 720, 666, 604, 571.
TLC: Rf 0.67 (cyclohexane, 100%, SiO2).
IR (neat, cmꢀ1): 2952, 2909, 2874, 1596, 1569, 1479, 1458,
1415, 1379, 1288, 1236, 1208, 1011, 989, 973, 805, 741, 717.
1H NMR (300 MHz, CDCl3): d 0.58 (q, 6H, J = 7.9 Hz), 0.92 (t, 9H,
J = 7.9 Hz), 2.30 (s, 3H), 6.22 (d, 1H, J = 19.2 Hz), 6.96–7.17 (m, 4H),
7.38-7.48 (m, 1H).
1H NMR (300 MHz, CDCl3): major b-isomer: d 0.62 (q, 6H,
J = 7.6 Hz), 0.94 (t, 9H, J = 7.6 Hz), 3.80 (s, 3H), 6.24 (d, 1H,
J = 19.2 Hz), 7.19 (td, 1H, J = 7.6 Hz, J = 1.2 Hz), 7.36 (td, 1H,
J = 7.6 Hz, J = 1.2 Hz), 7.48–7.61 (m, 2H), 7.76 (dd, 1H, J = 7.6 Hz,
J = 1.2 Hz).
13C NMR (75 MHz, CDCl3): d 3.8 (3 CH2), 6.9 (3 CH3), 19.8 (CH3),
125.4 (CH), 126.2 (CH), 127.8 (CH), 127.9 (CH), 130.4 (CH), 135.3
(C), 138.1 (C), 142.9 (CH).
13C NMR (75 MHz, CDCl3): major b-isomer: d 3.6 (3 CH2), 7.4 (3
CH3), 51.8 (OCH3), 127.2 (CH), 127.3 (CH), 128.5 (C), 129.2 (CH),
130.0 (CH), 132.0 (CH), 140.6 (C), 143.9 (CH), 168.0 (C).
MS(EI): 232 (M+).
1H NMR (300 MHz, CDCl3): minor
a-isomer: d 3.70 (s, 3H), 5.48
Anal. Calc. for C15H24Si (232.44): C, 77.51; H, 10.41. Found: C,
77.37; H, 10.30%.
(d, 1H, J = 3.0 Hz), 5.53 (d, 1H, J = 3.0 Hz). (Only the most significant
resonances are listed).
MS(EI): 276 (M+).
5.2.11. (E)-1-triethylsilyl-2-(4-methoxycarbonyl phenyl) -ethene (2k)
Yield: brown oil, 86%.
Anal. Calc. for C16H24O2Si (276.45): C 69.51, H 8.75 Found: C
69.29, H 8.70%.
TLC: Rf 0.32 (Et2O/cyclohexane, 5/95, SiO2).
IR (neat, cmꢀ1): 2952, 2910, 2874, 1721, 1605, 1564, 1458,
1435, 1409, 1308, 1274, 1242, 1215, 1194, 1174, 1106, 1016,
988, 969, 867, 843, 806, 782, 752, 690.
5.2.15. (E)-1-triethylsilyl-2-(4-pyridyl)ethene (2o)
Yield: yellow oil, 98%.
1H NMR (300 MHz, CDCl3): d 0.58 (q, 6H, J = 7.9 Hz), 0.89 (t, 9H,
J = 7.9 Hz), 3.81 (s, 3H), 6.49 (d, 1H, J = 19.3 Hz), 6.83 (d, 1H,
J = 19.3 Hz), 7.39 (d, 2H, J = 8.3 Hz), 7.90 (d, 2H, J = 8.3 Hz).
13C NMR (75 MHz, CDCl3): d 3.3 (3 CH2), 7.5 (3 CH3), 52.1 (CH3),
126.3 (2 CH), 129.1 (C), 129.8 (CH), 130.0 (2 CH), 142.7 (C), 143.8
(CH), 167.0 (C).
TLC: Rf 0.51 (Et2O/cyclohexane, 30/70, SiO2).
IR (neat, cmꢀ1): 3002, 2952, 2909, 2874, 1583, 1562, 1462,
1427, 1378, 1322, 1297, 1237, 1192, 1148, 1049, 993, 843, 785,
750, 719, 629, 565.
1H NMR (300 MHz, CDCl3): d 0.60 (q, 6H, J = 7.7 Hz), 0.92 (t, 9H,
J = 7.7 Hz), 6.85 (d, 1H, J = 19.2 Hz), 6.94 (d, 1H, J = 19.2 Hz), 7.00–
7.10 (m, 1H), 7.29 (d, 1H, J = 7.9 Hz), 7.55 (td, 1H, J = 5.9 Hz,
J = 1.7 Hz), 8.49 (d, 1H, J = 4.8 Hz).
MS(ESI): 277 (M+H)+, 299 (M+Na)+.
Anal. Calc. for C16H24O2Si (276.45): C, 69.51; H, 8.75. Found: C,
69.64; H, 8.53%.
13C NMR (75 MHz, CDCl3): d 3.4 (3 CH2), 7.4 (3 CH3), 121.3 (CH),
122.4 (CH), 131.4 (CH), 136.5 (CH), 144.6 (CH), 149.5 (CH), 156.0
(C).
5.2.12. (E)-1-triethylsilyl-2-(4-cyanophenyl)ethene (2l) [26]
Yield: yellow oil, 80%.
MS(EI): 219 (M+).
Anal. Calc. for C13H21NSi (219.40): C, 71.17; H, 9.65; N, 6.38.
Found: C, 71.23; H, 9.54; N, 6.23%.
TLC: Rf 0.62 (AcOEt/cyclohexane, 10/90, SiO2).
IR (neat, cmꢀ1): 2953, 2910, 2874, 2227, 1604, 1555, 1501,
1458, 1410, 1379, 1283, 1236, 1197, 1174, 1011, 988, 858, 839,
784, 723, 678, 579.
5.2.16. (E)-1-triethylsilylhept-1-ene (2p) [18b]
Yield: colorless oil, 93%.
1H NMR (300 MHz, CDCl3): d 0.44 (q, 6H, J = 7.8 Hz), 0.75 (t, 9H,
J = 7.8 Hz), 6.38 (d, 1H, J = 19.3 Hz), 6.66 (d, 1H, J = 19.3 Hz), 7.28 (d,
2H, J = 8.3 Hz), 7.39 (d, 2H, J = 8.3 Hz).
TLC: Rf 0.86 (cyclohexane, SiO2).
IR (neat, cmꢀ1): 2954, 2927, 2874, 1616, 1459, 1416, 1378,
1014, 991, 781, 717, 590.
13C NMR (75 MHz, CDCl3): d 3.5 (3 CH2), 7.5 (3 CH3), 111.1 (C),
119.1 (CN), 126.9 (2 CH), 131.7 (CH), 132.5 (2 CH), 142.7 (C), 143.0
(CH).
1H NMR (300 MHz, CDCl3): d 0.56 (q, 6H, J = 7.8 Hz), 0.83–1.01
(m, 12 H), 1.21–1.59 (m, 6H), 2.14 (m, 2H), 5.56 (d, 1H,
J = 18.7 Hz), 6.06 (dt, 1H, J = 18.7 Hz, J = 6.2 Hz).
13C NMR (75 MHz, CDCl3): d 3.7 (3 CH2), 7.5 (3 CH3), 14.2 (CH3),
22.7 (CH2), 28.6 (CH2), 31.5 (CH2), 37.2 (CH2), 125.6 (CH), 148.8
(CH).
MS(ESI): 266 (M+Na)+, 509 (2M+Na)+.
Anal. Calc. for C15H21NSi (243.42): C, 74.01; H, 8.70; N, 5.75.
Found: C, 73.97; H, 8.71; N, 5.63%.
MS(EI): 212 (M+). Anal. Calc. for C13H28Si (212.45): C, 73.50; H,
13.28. Found: C, 73.38; H, 13.05%.
5.2.13. (E)-1-triethylsilyl-2-(4-bromophenyl)ethene (2m)
Yield: yellow oil, 94%.
TLC: Rf 0.68 (cyclohexane, SiO2).
5.2.17. (E)-1-trietylsilyl-3-methoxy-but-1-ene (2q) [18b]
Yield: colorless oil, 96%.
IR (neat, cmꢀ1): 2952, 2908, 2873, 1603, 1587, 1560, 1485,
1458, 1415, 1396, 1379, 1327, 1236, 1212, 1197, 1072, 1008,
986, 846, 828, 806, 780, 717, 633, 581.
TLC: Rf 0.43 (Et2O/cyclohexane, 5/95, SiO2).
IR (neat, cmꢀ1): 2953, 2911, 2875, 2818, 1619, 1459, 1416,
1370, 1329, 1236, 1199, 1109, 1080, 1043, 992, 910, 849, 777,
717, 682.
1H NMR (300 MHz, CDCl3): d 0.58 (q, 6H, J = 7.7 Hz), 0.91 (t, 9H,
J = 7.7 Hz), 6.33 (d, 1H, J = 19.3 Hz), 6.74 (d, 1H, J = 19.3 Hz), 7.22 (d,
2H, J = 8.5 Hz), 7.37 (d, 2H, J = 8.5 Hz).
1H NMR (300 MHz, CDCl3): d 0.50 (q, 6H, J = 7.9 Hz), 0.88 (t, 9H,
J = 7.9 Hz), 1.16 (d, 3H, J = 7.1 Hz), 3.20 (s, 3H), 3.56-3.68 (m, 1H),
5.66 (d, 1H, J = 18.9 Hz), 5.82 (dd, 1H, J = 18.9 Hz, J = 6.5 Hz).
13C NMR (75 MHz, CDCl3): d 7.5 (3 CH2), 7.5 (3 CH3), 121.8 (C),
127.3 (CH), 127.9 (2 CH), 131.7 (2 CH), 137.5 (C), 143.6 (CH).

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A. Hamze et al. / Journal of Organometallic Chemistry 693 (2008) 2789–2797
13C NMR (75 MHz, CDCl3): d 3.5 (3 CH2), 7.4 (3 CH3), 21.2 (CH3),
Anal. Calc. for C13H20O2Si (236.38): C, 66.05; H, 8.53. Found: C,
65.98; H, 8.46%.
56.1 (CH3), 80.8 (CH), 127.8 (CH), 149.1 (CH).
MS(EI): 200 (M+).
Anal. Calc. for C11H24OSi (200.39): C, 65.93; H, 12.07. Found: C,
65.89; H, 12.03%.
5.2.22. (E)-1-triethoxysilyl-2-(4-methylphenyl)ethene (2v) [27]
Yield: yellow oil, 83% ratio of isomers /b (ca. 2/98).
a
TLC: Rf 0.21 (Et2O/cyclohexane, 5/95, SiO2).
IR (neat, cmꢀ1): 2974, 2926, 2885, 1610, 1568, 1511, 1442,
1390, 1293, 1197, 1166, 1099, 1072, 994, 956, 848, 824, 786.
1H NMR (300 MHz, CDCl3): d 1.10–1.26 (m, 9H), 2.28 (s, 3H),
3.70–3.90 (m, 6H), 6.04 (d, 1H, J = 19.4 Hz), 7.01–7.20 (m, 3H),
7.30 (d, 2H, J = 8.1 Hz).
5.2.18. (E)-3-Triethylsilylprop-2-en-1-ol (2r) [16]
Yield: colorless oil, 80%.
TLC: Rf 0.31 (Et2O/cyclohexane, 30/70, SiO2).
IR (neat, cmꢀ1): 3318, 2953, 2910, 2875, 1624, 1458, 1416,
1236, 1071, 1003, 785, 717.
1H NMR (300 MHz, CDCl3): d 0.60 (q, 6H, J = 7.9 Hz), 0.97 (t, 9H,
J = 7.9 Hz), 1.50 (brs, 1H), 4.21 (m, 2H), 5.87 (d, 1H, J = 19.0 Hz),
6.22 (dt, 1H, J = 19.0 Hz, J = 4.4 Hz).
13C NMR (75 MHz, CDCl3): d 18.3 (3 CH3), 21.0 (CH3), 58.6 (3
CH2), 116.3 (CH), 126.7 (2 CH), 129.3 (2 CH), 135.0 (C), 138.9 (C),
149.1 (CH).
13C NMR (75 MHz, CDCl3): d 3.5 (3 CH2), 7.4 (3 CH3), 65.9
(OCH2), 125.9 (CH), 146.2 (CH).
MS(ESI): 303 (M+Na)+.
Anal. Calc. for C15H24O3Si (280.43): C, 64.24; H, 8.63. Found: C,
64.14; H, 8.47%.
MS(ESI): 173, (M+H)+, 195 (M+Na)+.
Anal. Calc. for C9H20OSi (172.34): C, 62.72; H, 11.70. Found: C,
62.68; H, 11.54%.
5.2.23. (E)-1-ethoxydimethylsilyl-2-(4-methoxy-
carbonylphenyl)ethene (2w)
5.2.19. (E)-1-triethylsilylnon-1-en-4-ol (2s)
Yield: colorless oil, 78%.
Yield: colorless oil, 68%. ratio of isomers a/b (ca. 3/97).
TLC: Rf 0.60 (Et2O/cyclohexane, 10/90, SiO2).
IR (neat, cmꢀ1): 2955, 1720, 1606, 1565, 1435, 1409, 1276,
1251, 1216, 1196, 1176, 1104, 1075, 1017, 990, 946, 834, 780, 752.
1H NMR (300 MHz, CDCl3): d 0.16 (s, 6H), 1.11 (t, 3H, J = 7.0 Hz),
3.60 (q, 2H, J = 7.0 Hz,), 3.80 (s, 3H), 6.44 (d, 1H, J = 19.3 Hz), 6.89
(d, 1H, J = 19.3 Hz), 7.38 (d, 2H, J = 8.3 Hz), 7.88 (d, 2H, J = 8.3 Hz).
13C NMR (75 MHz, CDCl3): d ꢀ1.6 (2 CH3), 18.7 (CH3), 52.2
(OCH3), 58.7 (CH2), 126.6 (2 CH), 129.7 (C), 130.0 (2 CH), 130.2
(CH), 142.3 (C), 144.4 (CH), 167.0 (CO).
TLC: Rf 0.43 (Et2O/cyclohexane, 30/70, SiO2).
IR (neat, cmꢀ1): 3354, 2953, 2931, 2874, 1615, 1459, 1416,
1378, 1237, 1125, 994, 761, 717, 579 cmꢀ1
.
1H NMR (300 MHz, CDCl3): d 0.45 (q, 6H, J = 7.9 Hz), 0.76–0.94
(m, 12H), 1.11–1.54 (m, 8H), 2.06–2.20 (m, 1H), 2.26-2.37 (m,
1H), 3.54–3.64 (m, 1H), 5.62 (d, 1H, J = 18.8 Hz), 5.97 (ddd, 1H,
J = 18.8 Hz, J = 7.4 Hz, J = 6.0 Hz).
13C NMR (75 MHz, CDCl3): d 3.6 (3 CH2), 7.5 (3 CH3), 14.2 (CH3),
22.7 (CH2), 25.4 (CH2), 32.0 (CH2), 36.9 (CH2), 45.4 (CH2), 70.7 (CH),
130.9 (CH), 144.3 (CH).
MS(ESI): 265, (M+H)+.
Anal. Calc. for C14H20O3Si (264.39): C, 63.60; H, 7.62. Found: C,
63.48; H, 7.50%.
MS(EI): 256 (M+).
Anal. Calc. for C15H32OSi (256.50): C, 70.24; H, 12.57. Found: C,
70.35; H, 12.45%.
5.2.24. (E)-1-triethoxysilyl-2-(2-methylphenyl)ethene (2x)
Yield: yellow oil, 75%.
5.2.20. (E)-1-triethoxysilyl-2-(4-methoxyphenyl) ethene (2t) [24]
TLC: Rf 0.28 (Et2O/cyclohexane, 5/95, SiO2). ratio
of isomers and b.
a/b (ca. 3/97)
Yield: yellow oil, 65%; ratio a/b (2/98 of isomers).
a
IR (neat, cmꢀ1): 2974, 2926, 2885, 1602, 1569, 1481, 1442,
1390, 1292, 1210, 1166, 1099, 1072, 995, 956, 831, 776, 742.
1H NMR (300 MHz, CDCl3): d 1.35–1.50 (m, 9 H), 2.47 (s, 3 H),
3.93–4.10 (m, 6H), 6.23 (d, 1H, J = 19.2 Hz), 7.20-7.38 (m, 3H),
7.56–7.75 (m, 2H).
TLC: Rf 0.50 (Et2O/cyclohexane, 30/70, SiO2).
IR (neat, cmꢀ1): 3288, 2974, 2891, 2883, 1606, 1572, 1508,
1465, 1442, 1418, 1390, 1293, 1250, 1169, 1099, 1071, 1032,
994, 956, 832, 797, 776, 748, 709, 685, 640.
1H NMR (300 MHz, CDCl3): d 1.20 (t, 9H, J = 7.0 Hz), 3.72 (s, 3H),
3.80 (q, 6H, J = 7.0 Hz), 5.92 (d, 1H, J = 19.5 Hz), 6.80 (d, 2H,
J = 8.3 Hz), 7.08 (d, 1H, J = 19.5 Hz), 7.34 (d, 2H, J = 8.3 Hz).
13C NMR (75 MHz, CDCl3): d 18.3 (3 CH3), 55.3 (3 CH2), 58.7
(OCH3), 113.9 (2 CH), 114.7 (CH), 128.3 (2 CH), 130.6 (C), 133.7
(CH), 160.3 (C).
13C NMR (75 MHz, CDCl3): d 18.1 (3 CH3), 19.6 (CH3), 58.6 (3
CH2), 120.1 (CH), 125.4 (CH), 126.3 (CH), 128.5 (CH), 130.4 (CH),
135.8 (C), 137.0 (C), 146.9 (CH).
MS(ESI): 303 (M+Na)+.
Anal. Calc. for C15H24O3Si (280.43): C, 64.24; H, 8.63. Found: C,
63.97; H, 8.55%.
MS(ESI): 319 (M+Na)+.
Anal. Calc. for C15H24O4Si (219.40): C, 60.78; H, 8.16. Found: C,
60.65; H, 8.15%.
5.2.25. (E)-1-ethoxydimethylsilylhept-1-ene (2y)
Yield: yellow oil, 94%.
5.2.21. (E)-1-dimethylethoxysilyl-2-(4-methoxyphenyl) ethene (2u)
Yield: yellow oil, 83%.
TLC: Rf 0.66 (Et2O/cyclohexane, 10/90, SiO2).
IR (neat, cmꢀ1): 2958, 2926, 1618, 1460, 1390, 1250, 1166,
1107, 1078, 992, 945, 831, 789.
TLC: Rf 0.34 (AcOEt/cyclohexane, 5/95, SiO2).
IR (neat, cmꢀ1): 2959, 1605, 1572, 1509, 1464, 1418, 1390,
1295, 1248, 1170, 1104, 1075, 1034, 988, 945, 828, 794, 758,
740, 633.
1H NMR (300 MHz, CDCl3): d 0.00 (s, 6H), 0.67–0.77 (t, 3H,
J = 7.0 Hz), 0.90–1.35 (m, 9H), 1.96 (q, 2H, J = 7.0 Hz), 3.49 (qd,
2H, J = 7.0 Hz, J = 1.3 Hz), 5.45 (dd, 1H, J = 18.7 Hz, J = 1.4 Hz),
6.02 (dt, 1H, J = 18.7 Hz, J = 6.2 Hz).
1H NMR (300 MHz, CDCl3): d 0.15 (s, 6H), 1.11 (t, 3H, J = 7.0 Hz),
3.62 (q, 2H, J = 7.0 Hz), 3.70 (s, 3H), 6.15 (d, 1H, J = 19.3 Hz), 6.75-
6.82 (m, 3H), 7.29 (d, 2H, J = 8.6 Hz).
13C NMR (75 MHz, CDCl3): d ꢀ1.6 (2 CH3), 14.2 (CH3), 18.6 (CH3),
22.7 (CH2), 28.3 (CH2), 31.5 (CH2), 36.7 (CH2), 58.4 (OCH2), 127.2
(CH), 150.1 (CH).
13C NMR (75 MHz, CDCl3): d ꢀ1.5 (2 CH3), 18.7 (CH3), 55.4 (CH3),
58.6 (CH2), 114.0 (2 CH), 123.7 (CH), 128.0 (2 CH), 131.0 (C), 145.1
(CH), 159.9 (C).
MS(ESI): 201, (M+H)+.
Anal. Calc. for C11H24OSi (200.39): C, 65.93; H, 12.07. Found: C,
65.85; H, 11.91%.
MS(ESI): 237, (M+H)+.

A. Hamze et al. / Journal of Organometallic Chemistry 693 (2008) 2789–2797
2797
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IR (neat, cmꢀ1): 2974, 2876, 1391, 1335, 1252, 1206, 1106,
1049, 998, 947, 835, 796.
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3.38–3.84 (m, 6H), 4.87 (d, 1H, J = 3.8 Hz), 6.02 (d, 1H,
J = 19.1 Hz), 6.12 (dd, 1H, J = 19.1 Hz, J = 3.8 Hz).
13C NMR (75 MHz, CDCl3): d ꢀ1.7 (CH3), 15.4 (CH3), 18.6 (CH3),
58.6 (OCH2), 61.2 (2 OCH2), 102.5 (CH), 131.3 (CH), 144.5 (CH).
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Acknowledgement
The CNRS is gratefully acknowledged for financial support of
this research.
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